BFD plot, after 2 weekends I'm finally getting somewhere.

[kexodusc]

I've had this thing since mid-March, but last weekend (June 11) was the first time I could hook it up and fiddle around with it.

I have to say, this thing is worth every penny, I no longer have a big room induced suckout and bottom end boom, which has allowed me to turn the sub up without the annoying bass peaks. I had a difference of over 24 dB between my biggest peak and dip. Let's say a response +/- 12 dB...pretty bad. Now it's about +/- 5 dB. The graph doesn't include all actual measurements, there' s a 3 points in particular where my response still varies by 5 dB but I just never bothered to modify the spreadsheet.

On that note, my in room results are pretty odd....most on-line node/mode calculator's I've seen predict different behavior. I attribute this to the 2 doors, 2 windows, and half-foot countersunk walls along 1/2 the room...maybe sub position as well...anyway.

The BFD is as frustrating to learn at first as everyone mentions. But half an hour or so everynight and a few afternoons on weekends goes a long way.

My reference level was 64.5 dB, though I had originally done these at 80 and 70 dB. As I'd hoped, the results were pretty much linear except the dips were a bit lower relative reference at higher SPL. I chose the lower volume because there were too many buzzes and rattles adding a dB or two at some frequencies.

I would like to lower this curve overall by 1 or 2 dB, but it's not as simple as the knob on my sub amp or the receiver settings for some reason.

I'm definitely going to aim for the "house-curve, boosting frequencies below 40 Hz or by about 6 dB per octave, my hearing definitely drops off a bit down that low. I suspect I'll have to start all over again - it's unreal how boosting or cutting low frequencies affects the higher ones. I'll basically have to increase the gain on my amp and cut the frequencies above 40 Hz I think.

I'm also going to have to try all this again with the Radio Shack SPL meter if I ever get it back from my brother.. My Galaxy Audio SPL meter is much more accurate above 40 Hz, I'm not so sure about below that point though, and it'd be nice to double check.

All in all, this could be the best purchase in my home theater system to date. You really can't explain how much bass you are missing (or adding) once you tighten up the in-room response. I've also increased my crossover from 60 Hz back up to 80Hz because, well, it sounds alot better, the 15" sub doesn't betray it's location too much, and more consistent response is well worth the trade-off. Surprisingly this benefits multi-channel audio more than movies (probably because of bass management issues).

At $100 if you're still on the fence, go ahead and get one of these. It's a damn cheap upgrade that dramatically improves 2 or 3 octaves of info, and lets you squeeze the most out of your sub.

The blue curve is the measured in room response without the parametric eq, the pink curve is with parametric eq, the yellow is the reference level.